Gordon U.S. Pat. No. 5,222,589, depicted in FIG. 3, is directed to a conveyor belt cleaning system and discloses a belt wiper 3W which consists essentially a narrow flat base 3B with two constant radius arcs AL and AR starting at each corner of the narrow base 3B and meeting at a point forming the blade tip or scraper edge 3SE. These previous blades were attached to tensioning frames by a metal insert 3MI which has a short profile and cast within the elastic polymer blade body. Blade sidewall AL is concave towards the belt conveyor and the head pulley, and the other blade sidewall AR is convex away from the belt conveyor and head pulley.
This design produces a relatively long and narrow profile of limited structure rigidity (low moment of inertia and a long effective column length). Operational forces on this type of blade design produce relatively large bending moments which are resisted by the short profile metal mounting insert. Blades of this profile resist operational forces by the tip deflecting downward toward the base. The offset of the blade tip relative to the mounting insert produces this large bending moment when coupled with deflecting force at the tip (eccentrically loaded member).
The consequences of this profile design are that harder, less wear-resistant polymers should be used to compensate for the lack of structural rigidity and large bending moments. In severe cases, these conditions have caused a large number of blade failures in the field due to buckling, as the blade tips "curl under" when obstructions are encountered.